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Статті в журналах з теми "Extracellular Bacterial Protein (EBP)"
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Haggar, Axana, Muzaffar Hussain, Helena Lönnies, Mathias Herrmann, Anna Norrby-Teglund, and Jan-Ingmar Flock. "Extracellular Adherence Protein from Staphylococcus aureus Enhances Internalization into Eukaryotic Cells." Infection and Immunity 71, no. 5 (May 2003): 2310–17. http://dx.doi.org/10.1128/iai.71.5.2310-2317.2003.
Повний текст джерелаАнотація:
ABSTRACT In this study we have shown that Eap (extracellular adherence protein) plays a role in the internalization process of Staphylococcus aureus into eukaryotic cells. Eap is a protein that is mostly extracellularly and to a lesser extent is bound to the bacterial surface as a result of rebinding. Eap is able to bind to several plasma proteins, such as fibronectin, fibrinogen, and prothrombin. It has the capacity to form oligomers and is able to agglutinate S. aureus. A mutant strain, Newman mAH12 (eap:: Eryr), with a deficient eap gene was used in the present study. We have demonstrated that (i) strain Newman mAH12 could adhere to and become internalized to a higher extent by eukaryotic cells than the isogenic mutant, (ii) strain Newman mAH12 complemented with the eap gene displayed restoration of the internalization level, (iii) externally added Eap enhanced the internalization of laboratory and clinical S. aureus strains as well as of S. carnosus (a coagulase-negative species devoid of proteins important for internalization), and (iv) antibodies against Eap were able to block the internalization process in strain Newman mAH12 and clinical isolates. Eap, with its broad binding capacity and its surface localization, thus seems to contribute to the internalization of S. aureus into eukaryotic cells. We therefore propose a novel internalization pathway for S. aureus in which Eap plays an enhancing role.
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Bui, Long M. G., Peter Hoffmann, John D. Turnidge, Peter S. Zilm, and Stephen P. Kidd. "Prolonged Growth of a Clinical Staphylococcus aureus Strain Selects for a Stable Small-Colony-Variant Cell Type." Infection and Immunity 83, no. 2 (November 10, 2014): 470–81. http://dx.doi.org/10.1128/iai.02702-14.
Повний текст джерелаАнотація:
An undetermined feature ofStaphylococcus aureuspathogenesis is its persistence and then relapse of disease. This has been explained by its switch to alternative lifestyles, mainly as biofilm or small-colony variants (SCVs). Studying the native characteristics of SCVs has been problematic due to their reversion to the parental lifestyle. We have observed that for a number ofS. aureusstrains as they switch to an SCV lifestyle, there is the formation of an extracellular matrix. We focused our analysis on one strain, WCH-SK2. For bacterial survival in the host, the combination of low nutrients and the prolonged time frame forms a stress that selects for a specific cell type from the population. In this context, we used steady-state growth conditions with low nutrients and a controlled low growth rate for a prolonged time and with methylglyoxal. These conditions inducedS. aureusWCH-SK2 into a stable SCV cell type; the cells did not revert after subculturing. Analysis revealed these cells possessed a metabolic and surface profile that was different from those of previously described SCVs or biofilm cells. The extracellular matrix was protein and extracellular DNA but not polysaccharide. The SCV cells induced expression of certain surface proteins (such as Ebh) and synthesis of lantibiotics while downregulating factors that stimulate the immune response (leucocidin, capsule, and carotenoid). Our data reveal cell heterogeneity within anS. aureuspopulation and under conditions that resemble long-term survival in the host have identified a previously unnoticedS. aureuscell type with a distinctive metabolic and molecular profile.
3
Palma, Marco, Axana Haggar, and Jan-Ingmar Flock. "Adherence of Staphylococcus aureus Is Enhanced by an Endogenous Secreted Protein with Broad Binding Activity." Journal of Bacteriology 181, no. 9 (May 1, 1999): 2840–45. http://dx.doi.org/10.1128/jb.181.9.2840-2845.1999.
Повний текст джерелаАнотація:
ABSTRACT A novel mechanism for enhancement of adherence ofStaphylococcus aureus to host components is described. A secreted protein, Eap (extracellular adherence protein), was purified from the supernatant of S. aureus Newman and found to be able to bind to at least seven plasma proteins, e.g., fibronectin, the α-chain of fibrinogen, and prothrombin, and to the surface ofS. aureus. Eap bound much less to cells ofStaphylococcus epidermidis, Streptococcus mutans, or Escherichia coli. The protein can form oligomeric forms and is able to cause agglutination of S. aureus. Binding of S. aureus to fibroblasts and epithelial cells was significantly enhanced by addition of Eap, presumably due to its affinity both for plasma proteins on the cells and for the bacteria.
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Hussain, Muzaffar, Axana Haggar, Christine Heilmann, Georg Peters, Jan-Ingmar Flock, and Mathias Herrmann. "Insertional Inactivation of eap in Staphylococcus aureus Strain Newman Confers Reduced Staphylococcal Binding to Fibroblasts." Infection and Immunity 70, no. 6 (June 2002): 2933–40. http://dx.doi.org/10.1128/iai.70.6.2933-2940.2002.
Повний текст джерелаАнотація:
ABSTRACT To initiate invasive infection, Staphylococcus aureus must adhere to host substrates, such as the extracellular matrix or eukaryotic cells, by virtue of different surface proteins (adhesins). Recently, we identified a 60-kDa cell-secreted extracellular adherence protein (Eap) of S. aureus strain Newman with broad-spectrum binding characteristics (M. Palma, A. Haggar, and J. I. Flock, J. Bacteriol. 181:2840-2845, 1999), and we have molecularly confirmed Eap to be an analogue of the previously identified major histocompatibility complex class II analog protein (Map) (M. Hussain, K. Becker, C. von Eiff, G. Peter, and M. Herrmann, Clin. Diagn. Lab. Immunol. 8:1281-1286, 2001). Previous analyses of the Eap/Map function performed with purified protein did not allow dissection of its precise role in the complex situation of the staphylococcal whole cell presenting several secreted and wall-bound adhesins. Therefore, the role of Eap was investigated by constructing a stable eap::ermB deletion in strain Newman and by complementation of the mutant. Patterns of extracted cell surface proteins analyzed both by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by Western ligand assays with various adhesive matrix molecules clearly confirmed the absence of Eap in the mutant. However, binding and adhesion tests using whole staphylococcal cells demonstrated that both the parent and mutant strains bound equally well to fibronectin- and fibrinogen-coated surfaces, possibly due to their recognition by other staphylococcal adhesins. Furthermore, Eap mediated staphylococcal agglutination of both wild-type and mutant cells. In contrast, the mutant adhered to a significantly lesser extent to cultured fibroblasts (P < 0.001) than did the wild type, while adherence was restorable upon complementation. Furthermore, adherence to both epithelial cells (P < 0.05) and fibroblasts (not significant) could be blocked with antibodies against Eap, whereas preimmune serum was not active. In conclusion, Eap may contribute to pathogenicity by promoting adhesion of whole staphylococcal cells to complex eukaryotic substrates.
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Hinek, A., and M. Rabinovitch. "67-kD elastin-binding protein is a protective "companion" of extracellular insoluble elastin and intracellular tropoelastin." Journal of Cell Biology 126, no. 2 (July 15, 1994): 563–74. http://dx.doi.org/10.1083/jcb.126.2.563.
Повний текст джерелаАнотація:
The 67-kD elastin-binding protein (EBP) mediates cell adhesion to elastin and elastin fiber assembly, and it is similar, if not identical, to the 67-kD enzymatically inactive, alternatively spliced beta-galactosidase. The latter contains an elastin binding domain (S-GAL) homologous both to the aorta EBP and to NH2-terminal sequences of serine proteinases (Hinek, A., M. Rabinovitch, F. W. Keeley, and J. Callahan. 1993. J. Clin. Invest. 91:1198-1205). We now confirm the functional importance of this homology by showing that elastolytic activity of a representative serine elastase, porcine pancreatic elastase, was prevented by an antibody (anti-S-GAL) and by competing with purified EBP or S-GAL peptide. Immunohistochemistry of adult aorta indicates that the EBP exists as a permanent component of mature elastic fibers. This observation, together with the in vitro studies, suggests that the EBP could protect insoluble elastin from extracellular proteolysis and contribute to the extraordinary stability of this protein. Double immunolabeling of fetal lamb aorta with anti-S-GAL and antitropoelastin antibodies demonstrated, under light and electron microscopy, intracellular colocalization of the proteins in smooth muscle cells (SMC). Incubation of SMC with galactosugars to dissociate tropoelastin from EBP caused intracellular aggregation of tropoelastin. A tropoelastin/EBP complex was extracted from SMC lysates by coimmunoprecipitation and cross-linking, and its functional significance was addressed by showing that its dissociation by galactosugars caused degradation of tropoelastin by endogenous serine proteinase(s). This suggests that the EBP may also serve as a "companion" to intracellular tropoelastin, protecting this highly hydrophobic protein from self-aggregation and proteolytic degradation.
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Otto, Ben R., Silvy J. M. van Dooren, Jan H. Nuijens, Joen Luirink, and Bauke Oudega. "Characterization of a Hemoglobin Protease Secreted by the Pathogenic Escherichia coli Strain EB1." Journal of Experimental Medicine 188, no. 6 (September 21, 1998): 1091–103. http://dx.doi.org/10.1084/jem.188.6.1091.
Повний текст джерелаАнотація:
Many pathogenic bacteria can use heme compounds as a source of iron. Pathogenic Escherichia coli strains are capable of using hemoglobin as an iron source. However, the mechanism of heme acquisition from hemoglobin is not understood for this microorganism. We present the first molecular characterization of a hemoglobin protease (Hbp) from a human pathogenic E. coli strain. The enzyme also appeared to be a heme-binding protein. Affinity purification of this bifunctional protein enabled us to identify the extracellular gene product, and to clone and analyze its gene. A purification procedure developed for Hbp allowed us to perform functional studies. The protein interacted with hemoglobin, degraded it and subsequently bound the released heme. These results suggest that the protein is involved in heme acquisition by this human pathogen. Hbp belongs to the so-called IgA1 protease-like proteins, as indicated by the kinetics of its membrane transfer and DNA sequence similarity. The gene of this protein appears to be located on the large pColV-K30 episome, that only has been isolated from human and animal pathogens. All these characteristics indicate that Hbp may be an important virulence factor that may play a significant role in the pathogenesis of E. coli infections.
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Lee, Y. M., L. H. Miau, C. J. Chang, and S. C. Lee. "Transcriptional induction of the alpha-1 acid glycoprotein (AGP) gene by synergistic interaction of two alternative activator forms of AGP/enhancer-binding protein (C/EBP beta) and NF-kappaB or Nopp140." Molecular and Cellular Biology 16, no. 8 (August 1996): 4257–63. http://dx.doi.org/10.1128/mcb.16.8.4257.
Повний текст джерелаАнотація:
Alpha-1 acid glycoprotein/enhancer-binding protein (AGP/EBP) (C/EBPbeta), a member of the C/EBP family, is one of the key transcription factors responsible for the induction of a wide array of genes, some of which are expressed during the acute-phase response. Both activator and repressor were shown to be encoded by the intronless agp/ebp or its rat and human homologs, which contain a common bZIP domain at their C-terminal regions. Expression of the AGP gene (agp) is regulated by AGP/EBP in liver during the acute-phase response. However, the molecular mechanism for this regulation is poorly understood. The experiments reported here demonstrate that two activator forms of AGP/EBP, one of which has an additional 21 amino acids at its N-terminal region, are expressed in liver as well as in a number of cell lines. We have also demonstrated that NF-kappaB and a phosphoprotein of 140 kDa, Nopp140, interact with different AGP/EBP activators synergistically, which results in induction of the agp gene in an AGP/EBP-binding-motif-dependent manner. Furthermore, extracellular stimuli that are known to be NF-kappaB inducers can selectively activate the agp gene by cooperating with one of the two activator forms of AGP/EBP. The physiological significance of differential regulation for the function of two activator forms of AGP/EBP through selective interaction with different transcription factors is discussed.
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Jiang, J. G., and R. Zarnegar. "A novel transcriptional regulatory region within the core promoter of the hepatocyte growth factor gene is responsible for its inducibility by cytokines via the C/EBP family of transcription factors." Molecular and Cellular Biology 17, no. 10 (October 1997): 5758–70. http://dx.doi.org/10.1128/mcb.17.10.5758.
Повний текст джерелаАнотація:
Hepatocyte growth factor (HGF) is an inducible cytokine that is essential for the normal growth and development of various tissues, such as the liver. To decipher the molecular mechanisms that regulate HGF gene induction at the transcriptional level, we carried out in vitro and in vivo studies on the mouse HGF gene promoter. We have identified a novel regulatory element, located between -6 and +7 bp (from the transcription start site) in the HGF basal promoter region, which binds to inducible transcription factors and dictates responsiveness to extracellular stimuli that activate this gene. The core binding sequence for the inducible cis-acting factors was determined to be TTTGCAA (-4 to +3 bp) within the HGF promoter. Competition and gel mobility supershift assays showed that these binding complexes are composed of C/EBPbeta (CCAAT/enhancer-binding protein beta) and C/EBPdelta. DNA binding analysis also revealed that the binding site for the C/EBP family of transcription factors in the HGF promoter region overlaps that of another binding protein (complex C1), which binds specifically to a novel sequence with a core binding site of ACCGGT located adjacent to the C/EBP site (-9 to -4 bp). C1 binds to this region of the promoter and represses the inducible upregulation by C/EBP through direct competition for their individual binding sites. Partial hepatectomy, which is known to activate HGF gene expression in the liver, increased C/EBP (especially C/EBPbeta) binding activity to this region of the HGF promoter. Thus, our present results provide a mechanistic explanation for the transcriptional induction of the HGF gene by extracellular signals (i.e., cytokines) that induce tissue growth and regeneration.
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Kida, Yutaka, Hiroyoshi Inoue, Takashi Shimizu, and Koichi Kuwano. "Serratia marcescens Serralysin Induces Inflammatory Responses through Protease-Activated Receptor 2." Infection and Immunity 75, no. 1 (October 16, 2006): 164–74. http://dx.doi.org/10.1128/iai.01239-06.
Повний текст джерелаАнотація:
ABSTRACT The Serratia marcescens-derived protease serralysin is considered to play an important role in the pathogenesis of infection. Protease-activated receptor 2 (PAR-2) is activated by trypsin and also several other trypsin-like serine proteases, leading to the modulation of inflammatory and immune responses. However, little is known about the activation of PAR-2 by bacterial proteases and its roles in bacterial infection. In this study, we investigated whether S. marcescens serralysin activates host inflammatory responses through PAR-2. Our results demonstrated that serralysin induces interleukin-6 (IL-6) and IL-8 mRNA expression in a human lung squamous cell carcinoma, EBC-l cells. In addition, serralysin activated activator protein 1 (AP-1)-, CCAAT/enhancer-binding protein (C/EBP)-, and nuclear factor-κB (NF-κB)-driven promoters in EBC-1 cells. An electrophoretic mobility shift assay showed that serralysin activates the binding of AP-1, C/EBPβ, and NF-κB in the cells. Inactivation of serralysin resulted in the failure of transactivation of AP-1-, C/EBP-, and NF-κB-driven promoters in the cells. Furthermore, serralysin activated AP-1-, C/EBP-, and NF-κB-driven promoters via PAR-2 in HeLa cells. PAR-2 antagonist peptides decreased serralysin-induced transactivation of AP-1-, C/EBP-, and NF-κB-driven promoters in EBC-1 cells. Considered together, these results suggest that serralysin requires PAR-2 to activate the critical transcription factors AP-1, C/EBPβ, and NF-κB for host inflammatory responses.
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Kwak, Dong Hoon, Ji-Hye Lee, Dong-Gun Kim, Taesoo Kim, Kwang Jin Lee, and Jin Yeul Ma. "Inhibitory Effects of Hwangryunhaedok-Tang in 3T3-L1 Adipogenesis by Regulation of Raf/MEK1/ERK1/2 Pathway and PDK1/Akt Phosphorylation." Evidence-Based Complementary and Alternative Medicine 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/413906.
Повний текст джерелаАнотація:
Hwangryunhaedok-tang (HRT) has been long used as traditional medicine in Asia. However, inhibitory role of HRT is unclear in early stage of 3T3-L1 adipocyte differentiation related to signaling. In the present study, we investigated the inhibitory effects of HRT on upstream signaling of peroxisome proliferation-activity receptor-γ(PPAR-γ) and CCAAT/enhancer binding protein-β(C/EBP-β) expression in differentiation of 3T3-L1 preadipocytes. We found that HRT significantly inhibited the adipocyte differentiation by downregulating several adipocyte-specific transcription factors including PPAR-γ, C/EBP-α, and C/EBP-βin 3T3-L1 preadipocytes. Furthermore, we observed that HRT markedly inhibited the differentiation media-mediated phosphorylation of Raf/extracellular mitogen-activated protein kinase 1 (MEK1)/signal-regulated protein kinase 1/2 (ERK1/2) and phosphorylation of phosphoinositide-dependent kinase 1 (PDK1)/Akt. These results indicate that anti-adipogenesis mechanism involves the downregulation of the major transcription factors of adipogenesis including PPAR-γand C/EBP-αthrough inhibition of Raf/MEK1/ERK1/2 phosphorylation and PDK1/Akt phosphorylation by HRT. Furthermore, high performance liquid chromatography (HPLC) analysis showed HRT contains active antiobesity constituents such as palmatine, berberine, geniposide, baicalin, baicalein, and wogonin. Taken together, this study suggested that anti-adipogenesis effects of HRT were accounted by downregulation of Raf/MEK1/ERK1/2 pathway and PDK1/Akt pathway during 3T3-L1 adipocyte differentiation.
Дисертації з теми "Extracellular Bacterial Protein (EBP)"
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Haggar, Axana. "Interaction between Extracellular adherence protein (Eap) from Staphylococcus aureus and the human host." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-496-1/.
Повний текст джерела
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Shannon, Oonagh. "Biological effects of extracellular fibrinogen binding protein (Efb) in Staphylococcus aureus infection /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-275-6/.
Повний текст джерела
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Tiouajni, Mounira. "Caractérisation structurale et fonctionnelle du réseau d'interaction du Gelatin Binding Domain de la fibronectine humaine." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA114820.
Повний текст джерелаАнотація:
La matrice extracellulaire (MEC) intervient dans de nombreux processus biologiques tels que la migration, la différentiation ou l’adhésion cellulaire. Elle est également associée à plusieurs évènements pathologiques. La cohésion de la MEC est assurée par un réseau organisé et complexe de protéines présent au voisinage immédiat des cellules. Ce projet a pour objectif de contribuer à la caractérisation structurale et fonctionnelle de certaines de ces complexes protéiques. Le Gelatin Binding Domain (GBD) (⁶FI¹²FII ⁷⁸⁹FI), localisé dans la région N-terminale de la fibronectine est connu pour interagir avec la transglutaminase 2 (TG2), le collagène de type I, ou encore des protéines d’adhésion bactériennes tel que la FNE (protéine de Streptococcus equi). Mes travaux de thèse portent donc sur la caractérisation fonctionnelle et structurale de ces interactions par des approches biophysiques et biochimiques. Ce travail a permis de cartographier les régions d’interactionentre la TG2 et le GBD d’une part et la FNE et le GBD d’autre part. Nous avons par la suite entrepris une étude par SAXS des complexes TG2/GBD et FNE/GBD et réussi à établir des modèles structuraux d’interaction entre (1) le GBD et le domaine N-terminal de la TG2 et (2) entre la FNE et le sous fragment ⁷⁸⁹FI du GBD. La structure tridimensionnelle de la protéine FNE a été résolue par cristallographie aux rayons X grâce à l’utilisation d’un outil original facilitant l’obtention de cristauxThe extracellular matrix (ECM) is involved in a number of biological pathways associated with the cell migration, differentiation, adhesion and is also implicated in several pathological events. The cohesion of the ECM is accomplished by a highly organized protein complex network on the cell surface. The Gelatin Binding Domain (GBD) (⁶FI¹²FII ⁷⁸⁹FI) of the N-terminal region of fibronectin is found to interact with the transglutaminase 2 (TG2), collagen type I and the bacterial adhesion protein FNE. In this study, we conducted the structural and functional characterization of the protein complexes involved in the cohesion of ECM. The interactions between either TG2 or FNE and GBD have been characterized and the regions responsible for the interactions have also been mapped. Furthermore, we studied TG2/GBD and FNE/GBD complex by SAXS and built two models underscoring the interactions between (1), the GBD and the Nterminus of TG2 and (2), FNE and the sub-fragment ⁷⁸⁹FI of GBD providing insights on mechanistically elucidating the protein interactions during the cohehsion of ECM. The X-ray structure of the protein FNE of Streptococcus equi has been determined at 1.8 Å, by using an original tool that facilitates obtaining crystals
4
WU, ZHONGQIN. "Bacterial low temperature survival, ice nucleation proteins and ice-associating polymers." Thesis, 2010. http://hdl.handle.net/1974/5411.
Повний текст джерелаАнотація:
Microorganisms have developed ways to preserve cellular functions under low temperature conditions using a variety of biochemical adaptations including the modification of ice formation. In order to conduct a limited survey of microbial ice-associating strategies, a bacterial community associated with frost-exposed leaves was assessed by the construction of a 16S rDNA library, followed by the characterization of some isolates. Fifteen different species were identified based on their 16S rDNA. Among these, Pseudomonas syringae J6 had ice nucleation activity (INA), which promoted ice formation close to 0ºC, whereas Erwinia billingiae, Flavobacterium sp. and Sphingobacterium kitahiroshimense inhibited the recrystallization of small ice crystals at temperatures close to melting. The Erwinia billingiae isolate showed adhesive and swarming behaviour, which can be associated with biofilm formation. Visualization using negative staining, transmission electron microscopy and scanning electron microscopy confirmed the presence of flagella in addition to the presence of slimy biofilm architecture in these Erwina billingiae cultures. Subsequent purification of the extracellular polymeric substance followed by mass spectrometry allowed the identification of a putative outer membrane protein A, which may be involved in the protection of this bacterium to freeze-thaw cycles.
To further explore bacterial ice nucleation activity, an ice nucleation protein was cloned from Pseudomonas borealis, a bacterium originating from tundra soil, using degenerative PCR and chromosome walking. The sequence of the putative ice nucleation protein gene (inaPb) was cloned and expressed in Escherichia coli, and its identification was confirmed in the recombinant cells. Although the INPPb was more divergent than other plant-related bacterial INPs, it retained the highly conserved, repetitive core region. The protein may fold so that it has two flat faces, one for protein-protein interactions and the other for ice binding. Expression of the INPPb coding region fused to jelly fish green fluorescent protein showed a temperature-dependent polarized distribution of the recombinant protein in E. coli.
In summary, results from this thesis suggests that low temperature survival may be associated with a number of ice-associating adaptations including the presence of biofilm formation in Erwina billingiae amongst other bacteria, INA in P. borealis and INA-expressing recombinant E. coli.Thesis (Ph.D, Biology) -- Queen's University, 2010-01-27 11:47:02.385
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Zulfakar, SS. "Quantitative measurements of factors influencing bacterial attachment to meat surfaces." Thesis, 2013. https://eprints.utas.edu.au/17095/3/whole-thesis-Zulfakar.pdf.
Повний текст джерелаАнотація:
Pathogenic microbial contamination of meat can lead to foodborne illness following consumption of contaminated products. In abattoirs, contamination of carcass surfaces normally occurs when microorganisms are transferred from the outer surface of the carcass to sterile underlying tissues during slaughter and subsequent post-slaughter processes. Bacterial attachment to surfaces is a complex phenomenon that is influenced by many factors including the physicochemical properties of the bacterial cell and meat tissues, interacting surface structures and other factors.
The complexity and the heterogeneous nature of meat tissue, as well as physical entrapment within tissue fibres, have made it difficult to describe the specific tissue structures involved in the attachment process. A more systematic approach can be achieved by studying binding interactions between bacteria and specific structures of meat tissue.
Beef carcass prepared for commercial trade mainly consists of muscular and fatty tissue, bones and connective tissues. Approximately 49 to 68% of carcass weight consists of the muscular tissue whereas connective tissues are ubiquitous on the carcass surface, located at the fascia (between the skin and the skeletal tissues) and also within the muscle. The connective tissues are mainly composed of extracellular matrix (ECM) proteins.
This study aimed to determine the mechanisms of bacterial attachment to specific meat surface structures, namely the ECM proteins and muscle cells, by a range of enterohemorrhagic Escherichia coli (EHEC) and Salmonella spp. strains. The influence of physicochemical and environmental factors on attachment to meat structures was also investigated.
Attachment properties of the E. coli and Salmonella strains to four major ECM proteins (collagen I, fibronectin, collagen IV and laminin) were measured by a microtiter plate assay using crystal violet staining, and by epifluorescence microscopy. The effect of temperature (4, 25 and 37°C) and protein concentration were also determined. A wide variation in attachment to ECM proteins among strains was observed. In general, E. coli strains had a higher binding capacity to ECM proteins compared to Salmonella strains. Bacterial attachment was also found to be selective based on the anatomical location of the ECM proteins. Specifically, a higher proportion of strains attached to basement proteins (laminin and collagen IV) than to interstitial proteins (collagen I and fibronectin).
Protein concentration had a minor effect on bacterial attachment to ECM proteins; however attachment was significantly influenced by temperature. Highest attachment levels occurred at 4°C for collagen I and at 25°C for the other three ECM proteins. A strong positive correlation was found between the results of both the crystal violet and epifluorescence methods (r≥0.905, p<0.05) indicating that the former method is useful to study bacterial attachment to ECM proteins, especially in determining the attachment properties of high binding strains.
Based on these results, a subset of strains representing ‘high-‘, ‘intermediate-‘ and ‘low-‘ binding were chosen for further investigation. The influence of pH and salt (NaCl, KCl and CaCl\(_2\)) on attachment to ECM proteins was assessed in vitro. pH, within the range of 5 to 9, had no effect on attachment to ECM proteins, whereas the effect of salt type and concentration (0.1 – 5%) varied depending on strain-ECM protein combination. The effects of three chemical rinses commonly used in commercial abattoirs (2% acetic acid, 2% lactic acid and 10% trisodium phosphate (TSP)) on the attachment were also investigated. Rinses containing TSP were the most effective, producing >95% reduction in attachment to all ECM proteins. Acetic and lactic acids also markedly reduced bacterial attachment to ECM proteins, but at a lower level than TSP.
In addition to ECM proteins, bacterial attachment to animal muscle cells was measured. Specifically, attachment of E. coli and Salmonella strains to primary bovine muscle cells and a cultured muscle cell line, C\(_2\)C\(_{12}\), at 10 and 37°C was measured by plate-count assay. As shown for ECM proteins, attachment to muscle cells was strain dependant, with temperature being a significant factor. The attachment properties of the two muscle cell types differed significantly, indicating that C\(_2\)C\(_{12}\) cells are not suitable as surrogates for bovine muscle cells.
Finally, the specificity of interactions between bacterial cells and ECM proteins was studied. In general, addition of certain soluble ECM proteins had significant inhibitory or enhanced effects on binding interactions, depending on the type of ECM protein. For example, while soluble collagen IV inhibited attachment of E. coli M23Sr to laminin, basement membrane proteins increased attachment of E. coli EC614 and H10407 to the interstitial ECM proteins. However, soluble fibronectin did not affect binding interactions. These results could serve as the basis for future studies of potential synthetic analogs to inhibit bacterial attachment to meat surfaces.
Through this study, there is greater understanding of bacterial attachment to specific meat tissues. The knowledge obtained from this study may be beneficial in developing new and more targeted intervention systems for carcass decontamination, potentially reducing carcass contamination, product spoilage and health risk associated with meat.
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Chitayat, Seth. "NMR and Biophysical Studies of Modular Protein Structure and Function." Thesis, 2007. http://hdl.handle.net/1974/727.
Повний текст джерелаАнотація:
Proteins modularity enhances the multi-functionality and versatility of proteins by providing such properties as multiple and various ligand-binding sites, increased ligand affinity through the avidity effect, and the juxtaposition of ligand-binding modules near catalytic domains. An NMR-based "dissect-and-build" approach to studying modular protein structure and function has proven very successful, whereby modules are initially characterized individually and then correlated with the overall function of a protein. We have used the dissect-and-build approach and NMR to study two modular protein systems.
Chapter 2 details the NMR solution structure of the weak-lysine-binding kringle IV type 8 (KIV8) module from the apolipoprotein(a) (apo(a)) component of lipoprotein(a) was determined and its ligand-binding properties assessed. In vitro studies have demonstrated the importance of the apo(a) KIV7 and KIV8 modules in mediating specific lysine-dependent interactions with the apolipoproteinB-100 (apoB-100) component of LDL in the initial non-covalent step of lipoprotein assembly. Notable differences identified in the lysine binding site (LBS) of the KIV8 were deemed responsible for the differential modes of apoB-100 recognition by KIV7 and KIV8. In addition, the KIV8 structure has brought to light the importance of an RGD sequence at the N-terminus of the apo(a) KIV8 module, which may mediate important apo(a)-integrin interactions.
In Chapters 3-6, structure-function studies of the CpGH84C X82 and the CpGH84A dockerin-containing modular pair were conducted to understand how the varying modularity unique to the C-terminal regions of the secreted multi-modular family 84 glycoside hydrolases influences the spreading of Clostridium perfringens. Identification of a CpGH84C cohesin module (X82), and the structural characterization of a dockerin-containing modular pair provides the first evidence for multi-enzyme complex formation mediated by non-cellulosomal cohesin-dockerin interactions. The formation of large hydrolytic enzyme complexes introduces a novel mechanism by which C. perfringens may enhance its role in pathogenesis.Thesis (Ph.D, Biochemistry) -- Queen's University, 2007-09-27 11:46:38.753
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Chu, Mien-Sheng, and 朱勉生. "Role of cyclic AMP-dependent Kinase (PKA), Extracellular Signal-regulated Kinase (ERK) and p38 Mitogen-activated Protein Kinase (p38 MAPK) Pathways in Bacterial Endotoxin-induced Expression of Nitric Oxide Synthase II and Production of Nitric Oxide: Requi." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/85530499126278854895.
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碩士國立陽明大學
解剖暨細胞生物學研究所
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Upon inflammatory insults, microglia, the principal inflammatory cells in the brain, are capable of generating large amounts of regulatory factors, such as cytokines and nitric oxides (NO), that may play important roles in the pathogenesis of neurological diseases. In microglia, NO is produced by the inducible type of NO synthase (iNOS or NOS2) that was reported to be both neurodestructive and neuroprotective. Despite the numerous studies that have been conducted, the mechanisms for the regulation of NO biosynthesis remain to be elucidated. Expression of NOS2 in various phagocytic inflammatory cells can be strongly induced by the bacterial endotoxin, lipopolysaccharide (LPS). The bioactivity of LPS is mediated through a pertussis toxin-sensitive, Gi-protein-coupled receptor that, upon activation, results in down-regulation of adenylyl cyclase (AC), cyclic AMP (cAMP) levels, and the cAMP-dependent kinase (PKA) pathway. On the other hand, LPS has been shown to activate mitogen-activated protein kinases (MAPKs; including extracellular signal-regulated kinase, ERK, p38 MAPK, and c-Jun N-terminal kinase, JNK). The roles of the Gi-protein/AC/cAMP/PKA and Ras/Raf/MEK/MAPK pathways in the activation of various cell types have been well documented; however, the interaction between PKA and MAPKs, particularly in microglia, has rarely discussed. Because many neuroendocrine factors can activate the PKA pathway, the interactions between PKA and MAPK and their effect on NOS2 expression warrants further investigation. The purpose of this study is, therefore, to elucidate the effect of intracellular cAMP modulation on LPS-induced NOS2 expression and NO production in microglia cells. Using an immortalized murine microglia cell line, BV-2, stimulated with LPS, we measured NOS2 expression and NO production by immunoblotting assays and the Griess method, respectively, in the presence of various cAMP/PKA modulating agents. BV-2 cells, upon exposure to LPS, displayed detectable amounts of NOS2 in 3 hr. At 6 hr after LPS stimulation, accumulation of NO in the culture medium was detectable and reached maximum in 18 hr. The addition of a membrane-permeable cAMP (dibutyryl-cAMP; db-cAMP) or an AC-activating agent (forskolin) inhibited NO production relative to the concentration of cAMP added. On the other hand, additional of melatonin, a neurohormone with Gi-protein-coupled receptors also dose-dependently inhibited NO production, suggesting a lack of synergism by simultaneous down-regulation of PKA. Further examination of the effect of cAMP modulators on MAPK activation indicated that both ERK and p38 MAPK were essential for LPS-induced NOS2 expression; however, p38 appeared to play more important roles because a relatively low concentration of p38 inhibitor (SB203580) markedly suppressed NO production. CAMP and melatnonin alone caused activation of p38 MAPK and ERK, respectively. Pretreatment of BV-2 cells with cAMP or melatonin, however, inhibited the activation of p38 but had less effects on ERK. Our data provide a novel model for the interaction between PKA and MAPK. We propose that homeostasis of cAMP levels is crucial to MAPK-mediated signal for NOS2 expression. These results may prove to be insightful in the treatment of microglia-associated chronic inflammatory diseases of the brain.
Частини книг з теми "Extracellular Bacterial Protein (EBP)"
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Garcia, Roberto Alvarez-Fernandez, Guillermo Aragoneses-Cazorla, Laura Lerma, Rafael C. Prados-Rosales, and Jose L. Luque-Garcia. "Isolation of Bacterial Extracellular Vesicles and Identification of Their Protein Cargo." In Methods in Molecular Biology, 285–92. New York, NY: Springer US, 2023. http://dx.doi.org/10.1007/978-1-0716-3147-8_17.
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Evans, John Spencer, and Sunney I. Chan. "The N-terminal fragment of bovine phosphophoryn, an extracellular mineral matrix protein, shares sequence homology with viral, bacterial and eukaryotic transcriptional and post-translational regulatory proteins." In Proteins, 251–59. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-010-9063-6_35.
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Boggs, Amy Fujishige, and David A. Agard. "Bacterial extracellular secretion." In Membrane Protein Transport, 165–79. Elsevier, 1996. http://dx.doi.org/10.1016/s1874-592x(96)80007-2.
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LeBar, Kristen, and Zhijie Wang. "Extracellular Matrix in Cardiac Tissue Mechanics and Physiology: Role of Collagen Accumulation." In Extracellular Matrix - Developments and Therapeutics [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96585.
Повний текст джерелаАнотація:
The extracellular matrix (ECM) forms a mesh surrounding tissue, made up of fibrous and non-fibrous proteins that contribute to the cellular function, mechanical properties of the tissue and physiological function of the organ. The cardiac ECM remodels in response to mechanical alterations (e.g., pressure overload, volume overload) or injuries (e.g., myocardial infarction, bacterial infection), which further leads to mechanical and functional changes of the heart. Collagen, the most prevalent ECM protein in the body, contributes significantly to the mechanical behavior of myocardium during disease progression. Alterations in collagen fiber morphology and alignment, isoform, and cross-linking occur during the progression of various cardiac diseases. Acute or compensatory remodeling of cardiac ECM maintains normal cardiac function. However, chronic or decompensatory remodeling eventually results in heart failure, and the exact mechanism of transition into maladaptation remains unclear. This review aims to summarize the primary role of collagen accumulation (fibrosis) in heart failure progression, with a focus on its effects on myocardial tissue mechanical properties and cellular and organ functions.
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Patel, Hershna, and David B. Whitehouse. "Microbial Proteomics." In Genomics and Clinical Diagnostics, 103–38. The Royal Society of Chemistry, 2019. http://dx.doi.org/10.1039/9781782628217-00103.
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Proteomics is the large-scale and high-throughput study of proteins. A proteome is the population of all proteins expressed by the genome in a specific cell type, tissue or biological fluid at a particular time and under specific conditions. Any tissue, cell type or extracellular fluid is amenable to proteomic analysis. This chapter addresses the principles and practice of proteomics, focusing on microbial pathogens. An introduction to protein chemistry and analytical separation techniques is followed by a discussion of the technologies, approaches and applications of proteomics in the microbiology laboratory. Although the potential of proteomics for bacterial identification and characterisation remains to be fully realised, it is clear that this rapidly evolving science has already paved the way to aspects of cell biology and molecular pathology that were previously unattainable.
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Selwal, Krishan K., Garima Deswal, Harsha Nirvan, and Manjit K. Selwal. "Green Synthesis of Nanoparticles using Fungal Extracts." In Mycology: Current and Future Developments, 103–28. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815051360122030008.
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Nanotechnology involves the synthesis of nanoparticles (NPs) and paved the way for the possibility of applications in different fields such as pharmaceutical science, industry, environment and biosensor technology. The metal nanoparticles synthesis using fungal extract is gaining momentum due to their novel chemical, optical, electrical, and magnetic properties. The mycelial biomass is found to be more resistant against pH, temperature, agitation and pressure compared to bacterial and plant extract and thus more appropriate for industrial production. The nano-sized particles synthesized by green chemistry are of better quality than the ones made by chemical reduction methods such as laser ablation, metallic wire explosion, photochemical or radiation reduction and sonochemical method. The chemical methods can pose a risk to environmental and animal health due to release of the hazardous toxic component. Therefore, nanoparticles synthesis using fungal extract could be an ecofriendly alternative to chemical-based methods as green synthesis has the lesser possibility of such component release. The fungal extract comprises a plethora of secreted extracellular proteins, enzymes, vitamins and ions which are responsible for the reduction and stability of nano-size metallic particles. The biogenic nanoparticles thus produced have attained much interest due to their composition, shape and size, photochemical, optical and chemical properties. The nanomaterials have applications in various fields such as biosensor technology, DNA based techniques, metabolomics, antimicrobial agents, cancer cell treatment, protein engineering, purification of water and degradation of pesticides, synthetic biology, downstream processing and delivery of therapeutic compounds.
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Borkow, Gadi, and Eyal Melamed. "Copper, an Abandoned Player Returning to the Wound Healing Battle." In Wound Healing [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96952.
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Copper has two key properties that endow it as an excellent active ingredient to be used in the “wound healing battle”. First, copper plays a key role in angiogenesis, dermal fibroblasts proliferation, upregulation of collagen and elastin fibers production by dermal fibroblasts, and it serves as a cofactor of Lysyl oxidase needed for efficient dermal extracellular matrix (ECM) protein cross-linking. Secondly, copper has potent wide-spectrum biocidal properties. Both gram-positive and gram-negative bacteria, including antibiotic resistant bacteria and hard to kill bacterial spores, fungi and viruses, when exposed to high copper concentrations, are killed. Copper has been used as a biocide for centuries by many different civilizations. Impregnation of copper oxide microparticles in wound dressings allows continuous release of copper ions. This results not only in the protection of the wounds and wound dressings from pathogens, but more importantly, enhances wound healing. The article discusses the molecular mechanisms of enhanced wound healing by the copper oxide impregnated dressings, which include in situ upregulation of pro-angiogenic factors and increased blood vessel formation. It also includes clinical cases showing clearance of infection, induction of granulation and epithelialization of necrotic wounds, reduction of post-operative swelling inflammation and reduction of scar formation, in wounds when they were treated with copper oxide impregnated dressings. We show the positive outcome at all wound healing stages of using the copper impregnated wound dressings, indicating the neglected critical role copper plays in wound healing.
Тези доповідей конференцій з теми "Extracellular Bacterial Protein (EBP)"
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Zhang, D., Y. Zhu, and X. Wang. "Extracellular Vesicle-Containing Clara Cell Protein 16 (CC16) Regulates Bacterial-Induced Macrophage Activation." In American Thoracic Society 2020 International Conference, May 15-20, 2020 - Philadelphia, PA. American Thoracic Society, 2020. http://dx.doi.org/10.1164/ajrccm-conference.2020.201.1_meetingabstracts.a2291.
Повний текст джерелаЗвіти організацій з теми "Extracellular Bacterial Protein (EBP)"
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Barash, Itamar, J. Mina Bissell, Alexander Faerman, and Moshe Shani. Modification of Milk Composition via Transgenesis: The Role of the Extracellular Matrix in Regulating Transgene Expression. United States Department of Agriculture, July 1995. http://dx.doi.org/10.32747/1995.7570558.bard.
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Altering milk composition via transgenesis depends on three main factors. (1) The availability of an efficient regulatory sequences for targeting transgene(s) to the mammary gland; (2) a reliable in vitro model to test the expression of transgenes prior to their introduction to the animal genome; and (3) better understanding of the major factors which determine the rate of gene expression and protein synthesis. The current studies provide the necessary means and knowledge to alter milk protein composition via transgenesis. The following specific goals were achieved: a: Identifying regulatory regions in the b-lactoglobulin (BLG) gene and the cross-talk between elements which enabled us to construct an efficient vector for the expression of desirable cDNA's in the mammary gland. b: The establishment of a sheep mammary cell line that serves as a model for the analysis of endogenous and exogenous milk protein synthesis in the mammary gland of livestock. c: An accurate comparison of the potency of the 5' regulatory sequences from the BLG and whey acidic protein (WAP) promoters in directing the expression of human serum albumin (HSA) to the mammary gland in vitro and in vivo. In this study we have also shown that sequences within the coding region may determine a specific pattern of expression for the transgene, distinct from that of the native milk protein genes. d: Characterizing the dominant role of ECM in transgene expression in mammary epithelial cells. e: Further characterization of the BCE-1 enhancer element in the promoter of the b-casein gene as a binding site for the c/EBP-b and Stat5. Identifying its interaction with chromatin and its up regulation by inhibitors of histone deacetylation. f: Identifying a mechanism of translational control as a mediator for the synergistic effect of insulin and prolactin on protein synthesis in the mammary gland.
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Shani, Moshe, and C. P. Emerson. Genetic Manipulation of the Adipose Tissue via Transgenesis. United States Department of Agriculture, April 1995. http://dx.doi.org/10.32747/1995.7604929.bard.
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The long term goal of this study was to reduce caloric and fat content of beef and other red meats by means of genetic modification of the animal such that fat would not be accumulated. This was attempted by introducing into the germ line myogenic regulatory genes that would convert fat tissue to skeletal muscle. We first determined the consequences of ectopic expression of the myogenic regulatory gene MyoD1. It was found that deregulation of MyoD1 did not result in ectopic skeletal muscle formation but rather led to embryonic lethalities, probably due to its role in the control of the cell cycle. This indicated that MyoD1 should be placed under stringent control to allow survival. Embryonic lethalities were also observed when the regulatory elements of the adipose-specific gene adipsin directed the expression of MyoD1 or myogenin cDNAs, suggesting that these sequences are probably not strong enough to confer tissue specificity. To determine the specificity of the control elements of another fat specific gene (adipocyte protein 2-aP2), we fused them to the bacterial b-galactosidase reporter gene and established stable transgenic strains. The expression of the reporter gene in none of the strains was adipose specific. Each strain displayed a unique pattern of expression in various cell lineages. Most exciting results were obtained in a transgenic strain in which cells migrating from the ventro-lateral edge of the dermomyotome of developing somites to populate the limb buds with myoblasts were specifically stained for lacZ. Since the control sequences of the adipsin or aP2 genes did not confer fat specificity in transgenic mice we have taken both molecular and genetic approaches as an initial effort to identify genes important in the conversion of a multipotential cell such as C3H10T1/2 cell to adipoblast. Several novel adipocyte cell lines have been established that differ in the expression of transcription factors of the C/EBP family known to be markers for adipocyte differentiation. These studies revealed that one of the genetic programming changes which occur during 10T1/2 conversion from multipotential cell to a committed adipoblast is the ability to linduce C/EBPa gene expression. It is expected that further analysis of this gene would identify elements which regulate this lineage-specific expression. Such elements might be good candidates in future attempts to convert adipoblasts to skeletal muscle cells in vivo.